Many high security padlocks are commercially available. For example, Mul-T-Lock Ltd. produces C-Series Padlocks that include a single pin, for general use with commercially available hasps or heavy duty chains which accept 13 mm pins.
Padlocks that have protected hasps are also known. For example, U.S. Pat. No. 4,548,058 to Bahry and Dolev describes a padlock assembly in which each side of a door opening, e.g., a hinged door and a jamb, or two sliding doors, is provided with a protective hasp for a lock body and shackle of a lock. Each half of the hasp is so formed that, when mated, as on joining of the doors or closing of the doors, provisions are made for insertion of a lock body into the protective hasp, and insertion of a shackle through the hasp and the lock body to lock the closure. More specifically, the padlock assembly includes two complementary shells, which when abutting each other, enclose the entire padlock. Each shell has an opening from the top for the insertion of one leg of the shackle, and a larger opening from the bottom to house the lock body when the shells abut against each other. The shells provide the attachment means for the padlock on the door and jamb.